Make it so not all refractory recipes are the same. I don't know the real-life equivalent of this, I'm no metallurgist. But while I was excited to figure out that refractory gave me the possibility of more cool recipes, I was kind of disappointed that it gives the exact same boost to all metals in exactly the same way. Now I know you're not going for Pyanodon's level of complexity or realism, but what if you made one (or both) of these compromises:
Different metals have different probabilities of returning refracted materials. Maybe the ones with a lower IRL melting point would have a higher probability to give things back? Or maybe instead, the metals that are more heavily used in-game have a lower probability to give materials back? The first makes more realistic sense, but the second, to me, makes more gameplay sense, as return probability of the "not used in heavy amount" metals (e.g. Titanium) won't have a big gameplay effect, but having a different return for copper and iron will.
Different metals require different amounts of refracted material. Maybe iron uses 18 ore:3 graphite:1 silica, while copper might use 12 ore:1 graphite:2 silica. Then have each one return a percentage of the input material (e.g. iron would have a 70% to return 3 graphite while copper would have a 70% chance to return 2 silica). My little bit of Googling indicated to me that the real uses of graphite in metal casting do change based on the type of metal being cast - e.g. a denser graphite to cast brass and a more resistant graphite to cast nickel. Similarly to the above point, there's a decision to be made based on deciding whether a metal uses more or less material is based on real life metal properties or on gameplay functionality.
One day, I want to evaluate and perhaps vary the refractories used in the Foundry "X with refractory" recipes. I couldn't find good real-world examples on which metal casting used which refractories. (So, don't worry it won't be for a long time, and I may decide against it even then).
Thanks -- Yeah this general idea is on very low heat on the back burner right now. Thanks for your thoughts on it
Suggestion:
Make it so not all refractory recipes are the same. I don't know the real-life equivalent of this, I'm no metallurgist. But while I was excited to figure out that refractory gave me the possibility of more cool recipes, I was kind of disappointed that it gives the exact same boost to all metals in exactly the same way. Now I know you're not going for Pyanodon's level of complexity or realism, but what if you made one (or both) of these compromises:
(Source: Brevven)
(Source: Xynariz)